Alert archive / Florida / Severe Thunderstorm Warnings in 1986

Severe Thunderstorm Warning 12, NWS Miami, FL

May 21, 1986Broward County, Miami-Dade County, Florida

NWS Miami, FL issued this severe thunderstorm warning at May 21, 1986, 4:50 PM EDT for Broward County, Miami-Dade County, Florida. It was in force for 70 min. 2 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
May 21, 1986, 4:50 PM EDT (20:50 UTC)
Expired
May 21, 1986, 6:00 PM EDT
In force
70 min
Issued by
NWS Miami, FL
Area
Whole counties

Counties Broward County, FL, Miami-Dade County, FL

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

What was reported inside it

TimeReportWhereRemark
May 21, 5:45 PM EDTHail 1Miami-Dade, FL
May 21, 5:50 PM EDTHail 1Miami-Dade, FL

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.

The nearest sounding before it

Key West, FL (KEYW), launched 12:00Z, 8.8 hours before the alert went out and 193 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Key West, FL at 12:00Z on 1986-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1331 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Key West, FL at 12:00Z on 1986-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 18 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
1331 J/kg
Mixed-layer CIN
-54 J/kg
Mixed-layer LCL
1019 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
18 m²/s²
0-3 km storm-relative helicity
62 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KMIA 212050
SVRMIA
FLC011-025-212200-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM AND SPECIAL MARINE WARNING
NATIONAL WEATHER SERVICE MIAMI FL
450 PM EDT WED MAY 21 1986

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM AND 
SPECIAL MARINE WARNING EFFECTIVE UNTIL 600 PM EDT FOR PEOPLE IN THE 
FOLLOWING COUNTIES OF

SOUTHEAST FLORIDA...BROWARD AND DADE
...THIS WARNING ALSO INCLUDES THE ADJACENT COASTAL WATERS FOR THE
COUNTIES JUST MENTIONED

 THUNDERSTORM ACTIVITY WAS INTENSIFYING RAPIDLY OVER WESTERN
 PORTIONS OF BROWARD AND DADE COUNTIES DURING THIS EVENING RUSH
 HOUR PERIOD. NATIONAL WEATHER SERVICE RADAR AT 445 PM SHOWED
 SEVERAL THUNDERSTORMS...THE STRONGEST OF WHICH WERE OVER NORTHWEST
 DADE AND SOUTHWEST BROWARD COUNTIES...THAT ARE BECOMING SEVERE
 AND WILL LIKELY PRODUCE STRONG WIND GUSTS..HAIL..HEAVY RAIN..
 AND FREQUENT LIGHTNING.

 DADE AND BROWARD COUNTIES AND ADJACENT AREAS OF SOUTH FLORIDA
 ALSO REMAIN UNDER A SEVERE THUNDERSTORM WATCH UNTIL 7PM. THIS
 MEANS THAT OTHER SEVERE STORMS ARE LIKE TO DEVELOP THIS EVENING.

 RESIDENTS...EVENING RUSH HOUR COMMUTERS...AND BOATERS ALONG
 DADE AND BROWARD COASTAL WATERS SHOULD TAKE ACTION TO AVOID
 THESE STORMS.

IF THREATENING WEATHER APPROACHES YOU SHOULD GO TO A SAFE PLACE
IMMEDIATELY..AND YOU SHOULD ASK THE NEAREST LAW ENFORCEMENT AGENCY
TO RELAY YOUR SEVERE WEATHER REPORTS TO THE LOCAL NATIONAL WEATHER
SERVICE OFFICE.

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Special weather statement, May 21, 1:31 PM EDT, 3 hours 19 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE MIAMI FL
130 PM EDT WED MAY 21 1986

SEVERE THUNDERSTORM WATCH 204 IS IN EFFECT UNTIL 7 PM.

AT 130 PM NO SEVERE WEATHER HAS OCCURRED OVER SOUTH FLORIDA.

SCATTERED VERY HEAVY THUNDERSTORMS WERE INCREASING FROM BETWEEN
MELBOURNE AND VERO BEACH SOUTHWEST TO VENICE.

A FEW VERY HEAVY THUNDERSTORMS HAD FORMED FROM THE SOUTH PART
OF LAKE OKEECHOBEE TO NEAR IMMOKALEE.

THE STORMS *WERE MOVING EAST AT 25 MILES AN HOUR.
Special weather statement, May 21, 1:49 PM EDT, 3 hours 1 minute before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MIAMI FL
145 PM EDT WED MAY 21 1986

AT 145 PM EDT RADAR INDICATES AN AREA OF THUNDERSTORMS ARE
DEVLOPING RAPIDLY OVER THE NORTHEASTERN PART OF HENDRY CO1UNTY.
THESE STORMS WERE MOVING EAST NORTHEAST ABOUT 25 MPH TOWARDS
CLEWISTON FLORIDA AND WILL PRODUCE HEAVY RAIN..STRONG GUSTY WINDS
..FREQUENT LIGHTNING STRIKES AND POSSIBLE HAIL IN THE EFFECTED AREA
WITHIN THE NEXT HOUR OR TWO.
Special weather statement, May 21, 2:30 PM EDT, 2 hours 20 minutes before
^MIASPSPBI

SEVERE WEATHER AND MARINE STATEMENT
NATIONAL WEATHER SERVICE WEST PALM BEACH FL
230PM EDT WED MAY 21 1986

THE SEVERE THUNDERSTORM WATCH EFFECTIVE UNTILL 7PM EDT FOR A LARGE
PORTION OF SOUTH AND CENTRAL FLORIDA INCLUDING PALM
BEACH...MARTIN...ST LUCIE AND OKECHOBEE COUNTIES THEIR COASTAL WATERS
AS WELL AS LAKE OKECHOBEE CONTINUES IN EFFECT.

A SEVERE THUNDERSTORM WARNING AND SPECIAL MARINE WARNING IS IN EFFECT
FOR WESTERN PALM BEACH  AND MORTIN COUNTIES AS WELL AS LAKE OKEECHOBEE
UNTILL 345PM.

AT 230PM RADAR INDICATES SEVERE THUNDERSTORMS OVER SOUTHERN LAKE
OKEECHOBEE
AND HEAVY THUNDERSTORMS OVER NORTHERN OKECHOBEE COUNTY MOVING TOWARD
THE EAST NORTHEAST AROUND 20 MPH.

IF THREATENING WETHER APPROACHES TAKE COVER OR SEEK SAFE HARBOUR
IMMEDIATELY.

NO REPORTS OF SEVERE WEATHER HAVE BEEN RECEIVED SO FAR..HOWEVER TO
REPORT SEVERE WEATHER NOTIFY YOUR NEAREST LAW ENFORCEMENT AGENCY OR
CIVIL DEFENSE OFFICE.

REMEMBESR..A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE FAVORABLE
FOR SEVERE THUNDERSTORMS.

LISTEN TO YOUR LOCAL RADIO OR TV STATION OR NOAA WEATHER RADIO FOR
FURTHER STATEMENTS OR WARNINGS..WHICH WILL BE ISSUED IF CONDITIONS
WARRANT.
Special weather statement, May 21, 2:33 PM EDT, 2 hours 17 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE MIAMI FL
234 PM EDT WED MAY 21 1986

SEVERE THUNDERSTORM WATCH 204 IS IN EFFECT UNTIL 7 PM FOR THE
FOLLOWING COUNTIES OF SOUTH FLORIDA...GLADES HENDRY COLLIER MAINLAND
MONROE BROWARD DADE AND THE ADJACENT COASTAL WATERS.

AT 234 PM NO SEVERE WEATHER HAS OCCURRED OVER SOUTH FLORIDA.

SCATTERED VERY HEAVY THUNDERSTORMS CONTINUED FROM SOUTH OF LAKE
OKEECHOBEE NORTH TO SEBRING. THE TAREA EXTENDED TO NEAR THE EAST
COAST.

THE HEAVIEST STORMS CONTINUED IN NORTHEAST HENDRY COUNTY.

THE STORMS WERE MOVING EAST AT 25 MILES AN HOUR.
Special weather statement, May 21, 3:37 PM EDT, 1 hour 13 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE MIAMI FL
335 PM EDT WED MAY 21 1986

SEVERE THUNDERSTORM WATCH 204 IS IN EFFECT UNTIL 7 PM FOR THE
FOLLOWING COUNTIES OF SOUTH FLORIDA...GLADES HENDRY COLLIER MAINLAND
MONROE BROWARD DADE AND THE ADJACENT COASTAL WATERS.

AT 335 PM NO SEVERE WEATHER HAS OCCURRED OVER SOUTH FLORIDA.

SCATTERED VERY HEAVY THUNDERSTORMS WERE INCREASING FROM VERO BEACH
AND JUPITER TO JUST SOUTH OF L}AKE OKEECHOBEE.

A FEW VERY HEAVY THUNDERSTORMS HAD FORMED IN NORTHWEST DADE COUNTY.

THE STORMS WERE MOVING EAST AT 25 MILES AN HOUR.
Special weather statement, May 21, 4:35 PM EDT, 15 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE MIAMI FL
428 PM EDT WED MAY 21 1986

SEVERE THUNDERSTORM WATCH 204 IS IN EFFECT UNTIL 7 PM FOR THE
FOLLOWING COUNTIES OF SOUTH FLORIDA...GLADES HENDRY COLLIER MAINLAND
MONROE BROWARD DADE AND THE ADJACENT COASTAL WATERS.

AT 428 PM CLUSTERS OF VERY HEAVY THUNDERSTORMS...EMBEDDED IN LARGE AREAS
OF RAIN...CONTINUED OVER MOST OF THE EASTERN PENINSULA FROM INDIAN RIVER
COUNTY TO DADE COUNTY. THIS ACTIVITY EXTENDED INTO THE IMMEDIATE OFF-
SHORE WATERS.

THESE THUNDERSTORMS WERE MOVING TO THE EAST AT 20 MILES AN HOUR.

The office that day

Everything else NWS Miami, FL issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 20, 9:48 PM EDTSevere Thunderstorm WarningMFLBroward57 min
May 20, 10:42 PM EDTSevere Thunderstorm WarningMFLBroward, Miami-Dade63 min
May 21, 6:06 PM EDTSevere Thunderstorm WarningMFLBroward, Miami-Dade54 min
May 21, 6:59 PM EDTSevere Thunderstorm WarningMFLBroward, Miami-Dade61 min

Nearby

Severe Thunderstorm Warnings in Florida, 1986Every severe thunderstorm warning in 1986

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.